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Light mineral fillers are the natural inorganic materials of various compositions that have been used in a practical way since the beginning of the rubber industrial processing. Depending on the application, the natural kaolin is often modified by physical processes or by chemical processes (pillaring, adsorption, intercalation, functionalization, acid activation, etc.). It is important to modify kaolin due to improvement of its properties in order to adsorb the inorganic as well as organic molecules. In the introduced study, kaolin from Kaznějov deposit was modified by potassium acetate or dimethylsulphoxide and subsequently functionalized by accelerator dibenzothiazyldisulphide and its last modification was performed by silane treatment. Different techniques, such as the thermal (DTA) and spectral (FTIR) analysis were used to characterize modified kaolin samples. The main aim of the article is to observe the influence of modified kaolin forms on the physico-mechanical properties and structural changes of rubber mixtures. Combined with the carbon black, the given modified kaolin was mixed into a rubber blend in a particular ratio, which was5, 10, 24 phr. The effect of the modified kaolinite on the cure characteristics (minimum torque – ML, maximum torque – MH, optimal cure time – t90, scorch time ts2) and mechanical properties (tensile strength at break – TSb, elongation at break – Eb and hardness)in sulphur-cured rubber composites was investigated. In images from a scanning electron microscope (SEM), we observed the incorporation of modified forms of kaolin into the matrix of the rubber mixture.

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The presented work was dealing with the study of the commercial filler influence change in rubber blend by an alternative filler based on the clay mineral - illite. The focus of the presented work was aimed at the study of selected curing characteristics of rubber blend with addition of clay mineral filler and physico-mechanical properties of prepared vulcanizates. Curing characteristics, the processing safety, minimum and maximum torque, optimal curing time and curing rate coefficient were determined during the curing experiment phase. Selected physico-mechanical properties were given by the determination of hardness, tensibility and tensile strength. The obtained results proved the possibility of partial commercial filler replacement by an alternative filler and the positive effect of clay mineral on resulting important properties in rubber industry.

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